camera & lens fynction by topu.pdf
DESCRIPTION
photography classTRANSCRIPT
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Camera & Lens Function
1. Types of camera
2. Shutter
3. Aperture
4. Standard or Normal lens; Telephoto lens, Wide angle lens; Zoom lens.
Class Objectives
Camera How an image is formed
Optical Process
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Arabian scholar Ibn al Haitam, in the 10th century, described what can be called a camera obscura
The Human Camera
Eye
Large Format
Medium Format
Small format
Camera Types by Film size & Image Format
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Film size & Image Format
24 x 36mm
Range Finder Single Lens Reflex (SLR)
Camera Types by viewing system
Twin Lens Reflex (TLR)
Basic Camera Types
Conventional Camera
Depends on chemical, mechanical & optical process.
Digital Camera
It has sensors that converts light in to electrical charges which are then turned in to digital information.
Camera types by Technology
Panoramic Camera
Under Water Camera
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Different Parts of a SLR Hot Shoe
Film Rewind
Film Advance Lever
Shutter Release
Lens Lens Lock
Shutter Speed & Film speed Dial
Different Parts of a SLR
SLR- Single Lens Reflex
Professional Digital SLR
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All modern SLRs share some basic features: • A body
• A lens which is interchangeable.
• An adjustable aperture which is inside the lens.
• An adjustable shutter which is inside the body
• A built in TTL light meter Different Parts of a Digital SLR
Shutter Button
Lens Release Button Mode Dial
Hot Shoe
LCD Panel
Different Parts of a Digital SLR (Rear View)
Quick Control Dial LCD monitor
Viewfinder
Menu Button
Play Button
Erase Button
Lens
1550 Girolama Cardano recommends use of bi-convex lens in camera obscura to brighten image.
Lens is a cylinder of shaped pieces of glass (or plastic) that bend rays of light from the subject to create a sharp image on image plane (film/ sensor).
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Different Parts of a Lens
Focusing Ring
Aperture Ring
Focusing
Focusing is the process of moving the lens forward and backward until it produces the sharpest possible image of your main subject, or of the most important part of the scene, on the film in your camera.
Split- Image Focusing
Superimposed- Image Focusing
Ground-Glass Focusing
Automatic Focusing
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Focal Length
A lens’s focal length determines two things- 1. The first is how big your main subject will be in a photograph, a
variable called magnification. 2. The second is how much of a scene you can fit in a frame , a
variable called angle of view.
Focal length is the distance between the lens and its image (on the film) when the lens is focused at infinity. Focal length is expressed in millimeters, abbreviated mm.
7.5 mm
50 mm
135 mm
500 mm
28 mm
105 mm
300 mm
1000 mm
Angle of View & Magnification
50mm - Normal (or Standard) Lens for 35mm Cameras
When focused on a subject (s) “normal Lens” collects light rays from an angle of view about 50°- viewing things with about the same perspective as the human eye (when staring straight ahead with one eye closed).
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AC2 = AB2 + BC2 AC2 = (24) 2 + (36) 2
= 576 + 1296 = 1872 AC = 43.26 mm
AC2 = (6) 2 + (6) 2
= 36 + 36 = 72 AC =8.48 cm = 84.8 mm
A
B C
24mm
36 mm
135 Format
43.26 mm
When the Focal length of a lens Equals the diagonal measurement of the film the lens is considered normal.
The Normal Lens
What constitutes Normal depends on the film size.
A
B C
6 cm
6 cm
120 Format
8.48cm
A normal lens is the best choice when you want your lens to create an image in which the scene’s size relationships seem most natural.
Single- Focal- Length Lenses (Fixed-Focal-Length Lenses or
Prime Lens)
Zoom Lens (Variable Focal Lengths)
The Long Lens or The Telephoto Lens [Ex- 70mm, 85mm, 105mm, 300mm, 1000mm etc.]
Lenses with focal lengths much beyond 50mm (for 35mm cameras) are called both long lenses and telephoto lens. A telephoto lens magnifies the subject. This means they make the subject bigger (on the film and in the viewfinder) than it appears in life, without your having to move closer to it physically.
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Telephoto lenses ( example- 105mm or 135 mm) are popular for both candid photography (spontaneous people pictures) and street photography, because they
allow you to position yourself at a distance from the subject, so you can work more discreetly.
Telephoto lens is useful when you want to photograph something in the distance and you can’t or don’t want to get closer to the subject.
Nick Brandt
Also the effect of using the lens is to compress the picture space, making near and far elements seem physically closer together.
Steve McCurry Railway, Agra, 1983
The Wide Angle Lens [Ex- 14mm, 20 mm, 24mm, 28mm, 35mm ]
A wide angle focal length does just what it sounds like it does: it takes in a larger section of the scene you are photographing than you would get with a normal focal length. A wide angle makes subject look smaller than they would be rendered by a normal focal length. The most obvious time to use a wide angle lens is when you otherwise wouldn’t be able to get far enough away from a subject to include it all.
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Wide angle lens are valuable for setting up relationships between foreground and background (near and far) elements. Landscape photographers are specially fond of this tactic, composing with prominent foreground elements (rocks, plants, structures & so on) and also showing a wide expanse of background (mountains, sky and so on).
Photo
Saiful H
uq
A wide- angle focal length lets you get closer to the subject and it gives generous depth of field. So they are very popular among photojournalists.
Tele Zoom (Ex- 100-300mm)
Wide Angle Zoom (Ex- 12- 24 mm)
Wide angle- Tele zoom (Ex- 24-135 mm)
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Aperture
f-2.8
f-4
f-5.6
f-8
f-11
f-16
f-22
Moving to the next f/stop
number either halves or
doubles the amount of light.
Smaller f/stop numbers are larger lens openings and permits more light to pass to the film.
Larger f/stop numbers are smaller lens openings and reduce light passed to the film.
Depth Of Field
The distance range within which objects appear in acceptably sharp focus is commonly called the depth of field.
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Depth of Field
The distance range within which objects appear in
acceptably sharp focus is commonly called the depth of
field.
The wider the lens aperture, the shallower the depth of field.
Photo from Wikipedia
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Photo from Wikipedia Photo: Moinuddin
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Depth of Field & Aperture Size
Depth of Field & Camera Distance
Closer the subject narrower the DOF
Depth of Field & Changing lenses Shortest lens results in the greatest
DOF
Barbara Morgan
Shutter
The shutter speed determines how long the film or sensor is exposed to light.
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Moving the shutter speed dial to the next stop either halves or
doubles exposure time.
Shutter Speed
Shutter
B, 8,4, 2 ,1, 2,4,8,15,30,60,125,250,500,1000,2000...
B= Bulb 8= 8 seconds 1= 1 second 250= 1/250 second
Catching a Moment or Time Exposure [Shutter Priority]
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1/15 1/60 1/250 1/1000
Controlling Motion With Shutter Speed
Photo from Wikipedia
1/8 1/30 1/125
1/30 1/125 1/500
The direction in which a moving subject is traveling affects how high a shutter speed you’ll need.
Photo from Wikipedia
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Photo from Wikipedia
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Photo from Wikipedia Photo from Wikipedia
1. Types of camera- Small, medium & large format camera - View camera, TLR, Rangefinder & SLR.
2. Moving the shutter speed dial or the f-number to the next stop either halves or doubles exposure.
3. Use of Shutter: Exposure control, Catching a Moment or Time Exposure
4. Use of Aperture: Exposure control, Depth of field & Brightness control
5. Standard or Normal lens; Telephoto lens, Wide angle lens; Zoom lens.
Summary